Brake torque reactors for steerable wheels



Aug. 9, 1960 AL 'RONNING 7 2,948,545

BRAKE TORQUE'REACTORS FOR STBERABLE WHEELS Original Filed June 20, 19522 Sheets-Sheet 1 2/ FIE. l. l 22 INVENTOR. lbouw Ro/wvnvqmay! 47'TORIVEYS Aug. 9, 1960 A. RONNING BRAKE TORQUE REACTORS FOR STEERABLEWHEELS Original Filed June 20, 1952 2 Sheets-Sheet 2 INVENTOR. AoouwRomwuadrramvav;

BRAKE TORQUE REACTORS FOR STEERABLE WHEELS Adolph Running, 4826 E.Weldon Ave., Phoenix, Ariz.

Claims. (Cl. 280-87) My invention relates to brake torque reactors forthe brake-equipped steerable wheels of vehicles, and the primary objectis to provide reactor means for association with the brake systems ofsuch suspensions in such fashion as to counteract the undesirableeffects of brake torque reaction and bring about an increase in theaggregate braking efficiency as well as a reduction of undesirableeffects thereof upon steering the wheels. 7

Considering first the common motor vehicle wheel,

and brake assembly, there is a journal for the wheel and an axle onwhich the journal is carried and'by which the vehicle load istransmitted to the wheel. The common brake for such assembly includes anannular drum carried by and rotating with the wheel and a non-rotatingbacking plate carried by the stationary axle assembly, on which plateare the brake shoes which are applied to the drum to brake the Wheel.There are, of course, many variations of this general arrangement butall include relatively rotatively and non-rotating brake parts and myinvention is applicable to all. For convience sake, however, the presentdisclosure will relate to the common brake assembly as just described.Now when the wheel is braked, by applying the shoes to the drum, thereis set up what is called a brake torque reaction, the effect of which isto tend to cause the non-rotating parts to rotate with the rotatingparts, and the wheel. Of course, this force is resisted and thenon-rotating parts are not permitted to rotate with the wheel but inextreme cases, where the vehicle is heavily loaded, is travel-- ing athigh speed and the brakes are forcibly -applied, or in making what iscommonly known as a panic stop, this force is sufficient so that damagesometimes occurs to parts of the wheel assembly. In addition it isregarded as desirable to cushion the instantaneous application of thetorque to the supporting parts carrying the wheel since braking is thusmade smoother and less, likely to cause any of the known ill resultsresulting from the presentun-cushioned braking of the wheel.

The problems arising from this brake torque reaction are more acutewhere the wheels are swingably supported for up and down movement as inthe case ofwheel suspensions of the nature disclosed for example in myPatent No. 2,612,387, issued September 30, 1 952, in which it will. benoted that the wheels are arranged; in pairs, journaled on the rear.ends of cranked axles which are pivoted and differentially connected attheir forward ends for interdependent up and down swinging movementsabout their pivots. The purposeas explained in detail in that patent, isto differentiallycompensate. the wheels and equalize load distributiontheretounder all conditions, with transmission of minimum verticalacceleration or. deflection of the vehicle itself. The solution to theproblems arising from brake torque reaction in, such suspension is setforth and claimed in my copending application Serial No. 294,605, filedJune 20, 1952, for Brake Torque Reactors, now Patent N0. 2,812,953,issued November 12, 1957, fromwhich the-present application is adivision.

7 2,948,545 Patented Aug. 9, i960 The present invention is directed tocuring the undesirable eflects of brake torque reaction on steerablewheel suspensions, particularly and although not of necessity ofthediiferentially compensated type, such as disclosed as one example inmy Patent No. 2,650,100, issued August 2.5, 195 3. In this steerablesuspension the wheels are again carried at the rear ends of crankedaxles and these axles are pivoted and differentially connected at theirforward ends and are also arranged for dirigible movements in unisonabout an upright steering or caster axis. It will be noted that in suchdifferentially compensating suspensions the wheels are journaled on axleelements which may swing upwardly and downwardly and which trail fromforward points of steerable attachment to the vehicle. In consideringthe effect of brake torque upon these types of assemblies, it will bereadily understood that the brake torque reactive forces are normallyeffective about the axis of rotation of the wheels but that such forceswill have an angular component effective about the pivot axes of thecranked axles. From the outset I have believed that this brake torquereaction may possibly have a tendency to cause these wheels to in effectkick up very slightly when the brakes are forcibly applied with theresult that there may be a small but still very undesirable momentaryreduction in wheel and load contact with the road surface. Just whateffect this will have on the aggregate braking efficiency of all of thewheels of a vehicle is even now not entirely clear, but it is believedto be particularly desirable to counteract the effects of brake torquereaction upon steerable wheels and to apply the brake torque reaction tothe vehicle in some fashion which will tend to increase the aggregatebraking efficiency, and bypass the differential compensating mechanismconnecting the wheels where sameis used. It will, of course, berecognized by those skilled in the art that in high speed, over-the-roadvehicles any diminution of braking efficiency or interference withaccurate steering, however slight, is something to be avoided at allcosts.

Bearing in mind the foregoing aspects of brake torque reactionparticularly as regards steerable, differentially or swin'gably mountedwheels, it is the primary object of my invention to provide means, orwhat I prefer to call reactors, by which brake torque reaction may betransmitted directly from the wheel brakes to an adjacent steerablesupport and thence to the vehicle frame, completely bypassing thedifferential compensating mechanism where used, and without in the leastinterfering with either the steering or the up and down compensat,

ing movements of the wheels; and which by removing the effect of thistorque reaction from the axes of rotation of the wheels to pointsremoved from such axes it counteracts any kick up tendency which theremay be. In carrying out my invention I permit limited angulardisplacement or rotation of what has heretofore been the strictlystationary parts of the brake assemblies, so that the immediate effectof the torque, as the brakes are applied, is to tend to cause theseparts of the brake assemblies to instantaneously turn a short distancewith the Wheels. This very limited rotation of these brake parts, as thebrakes are applied, is used to distribute the torque reaction asbetween'the differentially compensated Wheels of my suspension even ifthe brakes are slightly uneven in adjustment so that load distributionas between the wheels remains constant and as a further object of theinvention I provide means for cushioning the limited movement and absorbat least a part of the shock forces incident to braking the wheels.

' The foregoing and other objects of my invention will be made clear inthe course of the following specification, and reference is now invitedto the accompanying drawings, wherein tion of the assembly of. Fig. lwith both wheels omitted.

but showing parts of the brake assemblies and both cranked axles andillustrating one form of link having longitudinal resiliency forcushioning torque reaction.

Fig. 3 is an enlarged and detail View, partially in section, of anotherform of link usable in the torque reactor of Fig. 1.

Fig. 4 is an enlarged fragmentary plan and sectional view taken ingeneral along the plane indicated by the line 4-4 in Fig. 1 andillustrating the manner in which the previously stationary part of thebrake mechanism is now arranged for limited rotation or oscillation.

Fig. 5 is a section along the line 5-5 in Fig. 4 illustrating thebearing structure for the brake mechanism and one manner in which therequisite fail-safe operation may be provided and the rotation of thispart of the brake mechanism positively limited under all. circumstances.

Referring now more particularly and by reference characters to thedrawing there is shown in Fig. l thereof a dual wheel, differentiallycompensating type of steerable suspension like that appearing in theparent application hereof and similar in many respects to that shown inmy prior Patent No. 2,650,100 herein'before identified. A and B isprovided with the wheels journaled for rotation upon the rear ends ofgenerally forwardly extending cranked axles iii, the rear ends of whichare provided with journals 11 for mounting the wheels. ends of the axleslit are provided with reversely and relatively inwardly turned trunnions12 by which they are journaled in a housing 13 carried upon or formed asa part of a generally upright steerable member or pedestal 14. Withinsaid housing 13 the aforesaid trunnions are operatively connected bymeshing, partially toothed gears 15 and the arrangement islthus suchthat the rear, wheel supported ends of the axles may swing relatively upand down, always in opposite directions, with a differentialcompensating action such that the wheels A-B will maintain road contacteven under rather rough surfaces with a minimum vertical acceleration ordeflection of the vehicle and, of course, so that the load from thevehicle will at all times be equally distributed between the wheels. Thesteerable member or pedestal 14 is here -shown as mounted for dirigiblemovements about a pin 16 carried by a transversely extending bolster 17which is mounted. for oscillation. in a transverse, vertical plane bymeans of a fore and aft extending pin 18 carried by bracket 19 aflixedto the vehicle, a mounting surface of which is designated at 20. In thisform of structure there will be a pair of wheel assemblies A-B, oneadjacent each end portion of the bolster 17, and provision is made forsteering these assemblies in unison by any suitable connection (notshown) to a steering arm 21 which is operatively connected to a bearing22 for the aforesaid pin 16 and to said member 14. On the other hand, ina tricycle type of vehicle only one such assembly of wheels A--B would,of course, be employed and at this point I make clear the fact that I donot restrict the application of the teaching of my presentinvention,insofar as it relates to the proper distribution of brake torquereactive forces from steerable wheels, to the dual wheel andcompensating type of vehicle suspension here illustrated. As will bereadily understood to those skilled in-the: art, a single steerableWheel carried for example upon a steering knuckle not' shown) might haveits brake torque reaction carried to thevehi- In this assembly a pair ofclose spaced wheels The forward do frame in a manner very like thatwhich will present- 1y appear, and this is regarded as with the scope ofthe present invention.

Turning for the moment to Figs. 4 and 5 it is seen that one of thecranked axles 10 is illustrated upon a larger scale along with.itsassociated Wheel B, which wheel has a suitable bearing 23 for rotatablemounting upon the aforesaid outwardly extending journal 11 of the axle.Forming a party of the overall structure of the wheel, of course, is abrake .assembly and the same includes a brake drum 24 which rotates withthe wheel and which is located: inwardly of the wheel rim 25. Alsoforming. a part of the brake assembly is a backing plate 26 and oneormore brake shoes, only one of which appears at 27. In the ordinaryinstance the backing plate 26 is rotationally stationary and the brakeshoes associated with this backing plate, when applied against the drum24, will frictionally brake the wheel under control of any suitable andwell known form of actuating means (not shown) whether it be hydraulic,vacuum or other type. In accordance with my invention, however, thebacking plate 26 is mounted for positively lim ited rotation as thebrakes are applied, with the wheel rotating in either direction, and forthis purpose the backing plate 26 is riveted or otherwise secured at 28upon a flanged bearing collar 29 rotatably mounted upon a bearingsurface 30 at the rear end of the axle 10 and, of course, coaxial withthe adjacent wheel journal 11. Axial displacement of the collar 29 isprevented by en.- gagement with an annular shoulder 31 formed upon. therear end of the axle 10 and with a retainer ring 32 engaged in aperipheral groove 33 in the axle immediately outward of the aforesaidbearing 39 as clearly appears in Fig. 4. For convenience in assemblythis retainer ring 32 may be made up in two semi-circular sectionsprovided with mating apertured lugs 34 at their extremities to receivetie bolts 35.

It is, of course, very important for safetys sake that this permissiblerotation of the brake backing plate 26 be positively limited and forthis purpose a radially pro jecting stop lug 36 is formedupon thebearing 30 and extends outwardly through an angularly extending slot 37formed in the collar 29 mounting the backing plate, as is best seen inFig. 5. Obviously the collar 29 and its associated backing plate 26 mayturn with the wheel as the brakes are applied only until the stop lug 36to a stop, or until thebrakes are released.

It will now beevident that as the brakes are appliedto thewheels A-Btheir associated backing plates 26 will tend to turn through a shortangular are or movement until haltedby the lug 36, as a result of braketorque reaction, and that this motion of the backing plate 26 willdirectly reflect the brake torque reactive forces as has been describedin detail in the application parent to this, now Patent No. 2,812,953.This limited motion of the backing plate 26, as a result of the reactiveforces of brake torque as the wheels are braked, is utilized to transmitand distribute these forces directly to the vehicle without interferingwith the steering of the wheels. It must be understood that these torquereactive forces, which become relatively tremendous at high speeds andduring hard braking, normally are effective about the axes of rotationof the wheels and this interferes with the steering of wheels of allvehicles to some extent and is particularly serious in connection withdual wheels of the differentially compensated type such as herein shown.For example, in braking steerable dual wheels of this kindif the brakesof one wheel are setup a bit tighter than the brakes of the other thenthe first wheel will have a tendency to dig in under hard braking,causing. the' opposite wheel to tend to move upward slightly and lose atleast some smallv fragment of its tractiveengagement withthe roadsurface. Furthermore,

in dual differentially compensated wheels the effects of brake torquereaction upon the gears or other mechanism connecting the axles '10 forinterdependent differentiating upward and downward movements inundesirable, and all of these factors become particularly aggravatedwhen the vehicle is traveling in a rearward direction;

' Now in Fig. 1 of the drawing- I show the flanged collar-29 of thebrake assembly'of the far wheel B asprovided with an integral lever arm40 extending radially with respect to the axis of rotation of the wheeland in, a generally upward direction. When this lever arm 40 is formedas'an integral part of the backing plate mount ing collar it isdesirable to provide thereon a stiffening rib 41, and in order to bringthe arm 40 inward from the wheel sufliciently to clear the rim thereofthe arm may be suitably bent as designated by the shade lines.Obviously, however, the lever arm.40 might be a separate part secured insome suitable way to the, brake backing plate 26 and I do 'notaccordingly limit myself to I motion of the lever arm 40 is resisted bymeans of a brake torque reactor in the form of a link 42, the rear endof which is pivoted at 43 to the upper end of the lever arm and theforward end of which is pivoted at 44 to thesteerable" member 14carrying the wheel. Thus the forces generated by brake torque reactionare transmitted directly to the said steerable member 14 and thence tothe supported vehicle, and inthe case of a rigid link of Fig. 1 therewould actually be no movement of the lever arm 40 at all, but as will bereadily understood to those skilled in this art the brake torquereaction is removed entirely from the Wheel and the axle structure,while the differential connecting mechanism is bypassed and the forcesapplied to the steerable member 14 thus accomplishing my ends in anexceedingly simple and satisfactory manner. There will, of course, be alever arm 40 and a brake torque reactor link 42 for each wheel A-B andthe links are arranged so that a line passing through their pivots 43-44will parallel a line intersecting the journals 11 and trunnions 12 ofthe associated axles so that each link and its axle acts in parallelmotion and there is no interference whatsoever with the differentiatingup and down movement as between the wheels.

It may be noted that particularly where a longitudinally non-elasticlink such as that shown at 42 is used the stop lug 36 and its associatedslot 37 cooperate simply to form a fail-safe mechanism so that breakageof the link, shearing of its pivots or even breakage of the lever arm 40will not render the brakes of the associated wheel ineffective.

It is desirable in my estimation that the application of the brakes towheels of the steerable variety, and particularly of the differentiallycompensating type, should be cushioned to some extent and this is madepossible by my arrangement of the brake backing plates for safe limitedrotational movement as the brakes are applied. For example, as is seenin Fig. 2, each link designated at 42 therein may be made up of frontand rear sections 42 and 42 one of which in efiect telescopes orslidably interfits into the other. Where these link sections 42 42overlap they may then be bonded together by rubber or other resilientmaterial, as seen at 45, by some of the known modern methods ofmanufacture so that yieldable and limited relative movement of the linksections is permitted or in effect so that the length of the linksthemselves may vary whether they are subjected to tension or compressionby the eifects of brake torque reaction. This relative movement of thelink sections will, of course, be quite limited but it will benevertheless suiiicient to slightly cushion the initial application ofthe brakes as will be understood.

In Fig. 3 I show another form of link for yieldably transmitting theeffects of brake torque reaction and the same is designated generally at46, having a rear rod portion 47 and a forward hollow portion 48 intowhich said rod slidably projects. The hollow section 48 of the link isformed with inwardly turned annular stops 49 and 5f? against which arebraced the opposite ends of a pair of expansion coil springs 51 and 52,the proximate ends of which are braced upon a collar 53 secured to therod section 47 in a central location. The springs 51152 thus resistrelative motion of the link sections 47-48 and this type of link may besubstituted for that shown in Fig. 2 if so desired.

It is understood that suitable modifications may be made in thestructure as disclosed, provided such modifications come within thespirit and scope of the appended claims. Having now therefore fullyillustrated and described my invention, what I claim to be new anddesire to protect by Letters Patent is:

1. In a wheel suspension including a steerable element and wheelsconnected thereto by differentially connected cranked axles swingable upand down with respect to said steerable element, brake mechanisms forthe wheels each comprising cooperating brake parts with one connected torot-ate with the wheel and the other connected to the axle, the latterbrake part being operatively journaled for limited rotation on the axleas the result of brake torque reaction, and a link element connectingeach of said axle mounted brake parts to the steerable element fortransmitting the brake torque reaction.

2. In a wheel suspension including a steerable element,

and wheels connected thereto by differentially connected cranked axlesswingable up and down with respect to said steerable element, brakemechanisms for the wheels each comprising cooperating brake parts withone connectedto rotate with the Wheel and the other connected to theaxle, the'latter brake part being operatively journaled for limitedrotation on the axle as the result of brake torque reaction, linkelements connecting said axle mounted brake parts to the steerableelement for transmitting the brake torque reaction, and the said linkelements operating in parallel motion with the cranked axles.

3. In a wheel suspension including a steerable element and wheelsconnected thereto by differentially connected cranked axles swingable upand down with respect to said steerable element, brake mechanisms forthe wheels each comprising cooperating brake parts with one mounted'torotate with the wheel and the other mounted on the axle, the latterbrake part being operatively journaled for limited rotation on the axleas the result of brake torque reaction, link elements connecting saidaxle mounted brake parts to the steerable element for transmitting thebrake torque reaction, and the said link elements being positionedparallel with lines passing through the axle pivots and the wheel axes.

4. In a wheel suspension including a steerable element and wheelsconnected thereto by diiierentially connected cranked axles swingable upand down with respect to said steerable element, brake mechanisms forthe wheels each comprising cooperating brake parts with one mounted torotate with the wheel and the other mounted on the axle, the latterbrake part being operatively journaled for limited rotation on the axleas the result of brake torque reaction, brake torque reactor linkspivoted at one end to each said brake part of limited rotation and thesteerable element, and each of said links paralleling its associatedaxle.

5. In a vehicle, a steerable support for the vehicle frame, comprising awheel, a steerable member operatively connecting the wheel to the frameand transmitting load from the frame to the wheel, brake mechanism forsaid wheel including. cooperating brake parts one rotatin'giwith thewheel and means mounting the other of said parts relative to saidsteerable member for only restricted rotation with the wheel as a resultof brake torque reaction forces when the wheel is braked, and braketorque reactor means distinct from said mounting means for said lastmentioned brake part and connecting the same through said steerablemember to the vehicle frame to transmit brake torque reaction to thevehicle frame.

6. A steerable wheel suspension for a vehicle frame, comprising incombination, a pair of close spaced and brake equipped wheels, crankedaxles having journals at their rear endsfor the respective wheels,differential mechanism swingably connecting the forward ends of theaxles for differential up and down movements at their rear ends, asteerable member supportablyand steerably connecting the saiddiiferential mechanism to the frame, and

mechanism operative to bypass the effects of brake torque reaction fromthe differential mechanism to transmit the same to the, frame.

7. A steerable wheel suspensionfora vehicle frame, comprising incombination, a pair of close spaced and brake equipped wheels, crankedaxles having journals at their rear ends for the respective wheels,differential mechanism swingably connecting the forward ends of theaxlesfor differential up and down movements at their rear ends, asteerable member supportably and steerably connecting the saiddifferential mechanism to the frame, and mechanism operative to bypassthe efiects of brake torque reaction from the difierential mechanism totransmit the same to the frame, said mechanism including linksparalleling the axles and connected from the respective wheel brakes tosaid steerable member.

8. A wheel suspension for a vehicle frame, comprising in combination, apair of close spaced and brake equipped wheels, cranked axles havingjournals at their rear ends for the respective wheels, differentialmechanism swingably connecting the forward ends of the axles fordifferential up and down movements at their rear ends, means supportablyand steerably connecting the forward ends of said axles to the frame,links connected between the wheel brakes and said steerable means andoperativeto remove theelfects of brake torque reaction from thedi-iferential'mechanism and transmit. the same to the frame; said linkseach including a pair of relatively longitudinally movable sections andrubber bonded to provide limited longitudinal elasticity.

9; A wheel suspension for a vericle frame, comprising in combination, apair of close spaced and brake equipped wheels, cranked axles havingjournals at their rear ends for the respective wheels, differentialmechanism swingably connecting the forward ends of the axlesfordiiferential up and down movements at their rear ends, means supportablyand steerably connecting the forward ends of said axles to the frame,links connected between the wheel brakes and said steerable means andoperative to remove the effects of brake torque reaction from thedifferential mechanism and transmit the same to the frame, said linkseach comprising relatively longitudinally movable sections, andoppositelyreacting springs operatively arranged to yieldably resistrelative movement of said sections in either direction with respect toeach other, one section of each said link enclosing both of saidsprings.

10. A steerable Wheel suspension for a vehicle frame, comprisingincombination, a pair of axles having journals at. their rear ends for therespective wheels, differential mechanismtswingably connecting the axlesfor difierential up and down movements at their rear ends, a steerablemember supportably and steerably connecting the said differentialmechanism to the frame, and mechanism operative for bypassing theeffects of torque reaction past the diiferentialv mechanism to theframe.

References Cited in the file of this patent UNITED STATES PATENTS1,841,415 Moorhouse Jan. 19, 1932 2,078,210 Sanford Apr. 20, 19372,241,193 Garnett May 6, 1941 2,244,853 Ronning June 10, 1941 2,520,778Page Aug. 29, 1950

